Detecting oil contamination and deterioration, in an internal combustion engine, is important in promoting and prolonging the useful life of the engine and engine oil.
The usable life of motor oil depends on many factors, including the type of oil used, the engine's condition, ambient operating conditions, driving habits, vehicle usage, and vehicle servicing. While most car manufacturers recommend changing the engine oil of an automobile at three months or three thousand miles, whichever comes first, many automobile owners and operators fail to regularly change the engine oil of their automobile within the recommended time frame.
Where deteriorated oil is subject to prolonged use because of infrequent oil changes, the useful life of an automobile engine is greatly reduced. The useful life of an automobile engine may also be reduced by the introduction of contaminants in the engine oil such as: water, antifreeze, or improper types of oil (e.g. four-stroke oil in a two-stroke engine). Accordingly, some types of oil monitoring methods and equipment, for detecting deterioration and contamination of engine lubricating oil, have been created.
Engine oil may contain fine carbon particulates (e.g., 0.03 μm to 0.05 μm) and larger metal particulates (e.g., 3 μm to 5 μm). It is therefore very important to determine the type and the quantity of such particulates. Prior art sensors are adequate for some oil quality detection application. Generally, however, such sensors have difficulty in detecting particulates, particularly because the sensing results are lumped into an overall detection data category and it is difficult to determine types of particulates and the varying particulate sizes. It is believed that a solution to this problem involves implementing the improved detection devices and techniques disclosed in greater detail herein. Optical scattering sensors, i.e., smoke alarms and turbidity sensors could be used as particulate sensors but they are sensing the lumped result and can't tell the difference among particulates with different sizes.